To provide a method separating a collagen, chitin compound material which is obtainable only from comparatively hard fish scale collected by artificially peeling, into a water-soluble low molecular weight compound material and an insoluble polymeric compound material by controlling high pressure processing condition and to provide a method of applying the same to food or the like.

This method produces the water-soluble low molecular weight compound material and the insoluble polymeric compound material by adding about six times of purified water to the transparent, lamellar crude collagen, chitin compound material which is obtained from a specific fish scale, and then sequentially carrying out a boiling or a high-pressure treatment, and the method applying the products to food.